package app

import (
	"context"
	"fmt"
	"time"

	"gitea.maximumdirect.net/eric/weatherreporter/internal/briefing"
	"gitea.maximumdirect.net/eric/weatherreporter/internal/collect"
	"gitea.maximumdirect.net/eric/weatherreporter/internal/fileutil"
	"gitea.maximumdirect.net/eric/weatherreporter/internal/generatedtext"
	"gitea.maximumdirect.net/eric/weatherreporter/internal/module"
	"gitea.maximumdirect.net/eric/weatherreporter/internal/promptdebug"
	"gitea.maximumdirect.net/eric/weatherreporter/internal/promptexec"
	"gitea.maximumdirect.net/eric/weatherreporter/internal/promptinput"
	"gitea.maximumdirect.net/eric/weatherreporter/internal/report"
	"gitea.maximumdirect.net/eric/weatherreporter/internal/state"
)

type promptReportRequest struct {
	GenerateRequest
	Resolved    report.Resolved
	Collection  collect.Result
	Inspection  PromptInspectionResult
	DebugWriter *promptdebug.PromptDebugWriter
	noNotify    bool
}

func generatePromptReport(ctx context.Context, req promptReportRequest) (*ReportResult, error) {
	workflow, err := newPromptReportWorkflow(ctx, req)
	if err != nil {
		return nil, err
	}
	if err := workflow.buildInputs(); err != nil {
		return workflow.result, err
	}

	execution, executeErr := workflow.executePrompt()
	if executeErr != nil {
		return workflow.result, workflow.handleExecutionFailure(executeErr)
	}
	if execution == nil {
		err := promptexec.NewError(promptexec.Generation, "prompt executor returned no execution", nil)
		if saveErr := workflow.persistOperationalExecutionFailure(err); saveErr != nil {
			return workflow.result, saveErr
		}
		return workflow.result, workflow.reportError("execute prompt", err)
	}
	if err := workflow.persistExecutionDebug(*execution); err != nil {
		return workflow.result, err
	}

	if execution.Validation.Status != promptexec.ValidationPassed && execution.Validation.Status != promptexec.ValidationFailed {
		err := promptexec.NewError(promptexec.OperationalValidation, "prompt execution did not complete validation", nil)
		if saveErr := workflow.persistOperationalExecutionFailure(err); saveErr != nil {
			return workflow.result, saveErr
		}
		return workflow.result, workflow.reportError("validate prompt execution", err)
	}
	if err := workflow.persistCompletedExecution(*execution); err != nil {
		return workflow.result, err
	}
	if execution.Validation.Status == promptexec.ValidationFailed {
		err := promptexec.NewError(promptexec.ValidationRejected, "prompt output did not satisfy its schema", nil)
		return workflow.result, workflow.reportError("validate prompt execution", err)
	}

	rendered, err := workflow.persistGeneratedContent(execution.RawOutput)
	if err != nil {
		return workflow.result, err
	}
	return workflow.finalizeReport(rendered)
}

type promptReportWorkflow struct {
	ctx               context.Context
	req               promptReportRequest
	store             state.Store
	result            *ReportResult
	metadata          state.Metadata
	briefingMetadata  briefing.Metadata
	reportFacts       ReportFacts
	moduleSnapshot    module.Snapshot
	dataPackageBytes  []byte
	handler           generatedtext.Handler
	executionArtifact state.PromptExecutionArtifact
	debugRef          promptdebug.PromptDebugRef
	prepared          bool
	callbackFailed    bool
}

func newPromptReportWorkflow(ctx context.Context, req promptReportRequest) (*promptReportWorkflow, error) {
	if req.Collection.Bundle == nil {
		return nil, fmt.Errorf("collected weather bundle is required")
	}
	store := req.Store
	var err error
	if store == nil {
		store, err = defaultStore(req.Config)
		if err != nil {
			return nil, err
		}
	}
	return &promptReportWorkflow{ctx: ctx, req: req, store: store}, nil
}

func (w *promptReportWorkflow) buildInputs() error {
	paths, err := w.store.Paths(w.req.Resolved)
	if err != nil {
		return err
	}
	w.result = &ReportResult{}
	w.reportFacts, err = BuildReportFacts(ModuleSnapshotRequest{Config: w.req.Config, Resolved: w.req.Resolved}, w.req.Collection.Bundle)
	if err != nil {
		return generatedReportError(w.req.Resolved, w.req.Resolved.Metadata().RunID, "build report facts", err)
	}
	w.moduleSnapshot, err = BuildModuleSnapshotFromFacts(ModuleSnapshotRequest{Config: w.req.Config, Resolved: w.req.Resolved}, w.reportFacts)
	if err != nil {
		return generatedReportError(w.req.Resolved, w.req.Resolved.Metadata().RunID, "build module snapshot", err)
	}
	moduleSnapshotPath, err := w.store.SaveModuleSnapshot(w.ctx, w.req.Resolved, w.moduleSnapshot)
	if err != nil {
		return err
	}
	w.result.ModuleSnapshot = w.moduleSnapshot
	w.result.ModuleSnapshotPath = moduleSnapshotPath
	w.briefingMetadata = briefing.BuildMetadata(briefingBuildContext(w.req.Config, w.req.Resolved, w.reportFacts.Collected))
	w.metadata = state.BuildPromptMetadataFromBriefingMetadata(w.req.Resolved, w.briefingMetadata, state.ArtifactPaths{
		ModuleSnapshot: moduleSnapshotPath,
		Metadata:       paths.Metadata,
	})
	w.result.Metadata = w.metadata
	dataPackage, err := promptinput.Build(promptinput.BuildRequest{
		Metadata: promptMetadata(w.metadata), Modules: w.moduleSnapshot,
	})
	if err != nil {
		return w.reportError("build data package", err)
	}
	w.dataPackageBytes, err = promptinput.MarshalYAML(dataPackage)
	if err != nil {
		return err
	}
	dataPackagePath, err := w.store.SaveDataPackageBytes(w.ctx, w.req.Resolved, w.dataPackageBytes)
	if err != nil {
		return err
	}
	w.metadata.DataPackagePath = dataPackagePath
	w.result.DataPackage = dataPackage
	w.result.DataPackagePath = dataPackagePath
	w.result.Metadata = w.metadata
	w.handler, err = generatedtext.LookupDefinition(w.req.Resolved.Definition)
	if err != nil {
		return w.reportError("lookup generated text catalog", err)
	}
	w.debugRef = promptdebug.PromptDebugRef{
		ReportID: w.req.Resolved.Definition.ID, ValidDate: w.req.Resolved.ValidPeriod.Start.Format("2006-01-02"), RunID: w.metadata.RunID,
	}
	return nil
}

func (w *promptReportWorkflow) executePrompt() (*promptexec.Execution, error) {
	return w.req.Executor.Execute(w.ctx, promptexec.ExecuteRequest{
		PromptID: w.req.Inspection.PromptID, PromptVersion: w.req.Inspection.PromptVersion,
		ProfileID: w.req.Inspection.ProfileID, DataPackage: w.dataPackageBytes,
		DataPackagePath: w.result.DataPackagePath, CaptureDebug: w.req.DebugWriter.Enabled(),
	}, w.persistPreparation)
}

func (w *promptReportWorkflow) persistPreparation(preparation promptexec.Preparation, debug *promptexec.PreparationDebug) error {
	artifact := state.PromptPreparationArtifact{
		SchemaVersion: state.PromptPreparationSchemaVersion, Status: state.PromptPreparationSucceeded,
		ReportID: w.req.Resolved.Definition.ID, RunID: w.metadata.RunID,
		PromptID: w.req.Inspection.PromptID, PromptVersion: w.req.Inspection.PromptVersion,
		DataPackagePath: w.result.DataPackagePath, Preparation: &preparation,
		StartedAt: preparation.StartedAt, EndedAt: preparation.EndedAt, Duration: preparation.Duration,
	}
	path, err := w.store.SavePromptPreparation(w.ctx, w.req.Resolved, artifact)
	if err != nil {
		w.callbackFailed = true
		return err
	}
	w.prepared = true
	w.result.PreparationPath = path
	w.metadata.PreparationPath = path
	w.result.Metadata = w.metadata
	debugPath, err := w.req.DebugWriter.WritePreparation(w.debugRef, preparation, debug)
	if err != nil {
		w.callbackFailed = true
		return promptDebugWriteError(err)
	}
	if debugPath != "" {
		w.result.LLMDebugPath = debugPath
	}
	if err := w.saveMetadata(); err != nil {
		w.callbackFailed = true
		return err
	}
	return nil
}

func (w *promptReportWorkflow) handleExecutionFailure(executeErr error) error {
	if w.callbackFailed {
		return executeErr
	}
	executeErr = classifiedPromptError("prompt execution failed", executeErr)
	if !w.prepared {
		if err := w.persistPreparationFailure(executeErr); err != nil {
			return err
		}
		return w.reportError("prepare prompt", executeErr)
	}
	if promptexec.CategoryOf(executeErr) != "" {
		if err := w.persistOperationalExecutionFailure(executeErr); err != nil {
			return err
		}
	}
	return w.reportError("execute prompt", executeErr)
}

func (w *promptReportWorkflow) persistPreparationFailure(executeErr error) error {
	startedAt, endedAt := time.Now(), time.Now()
	artifact := state.PromptPreparationArtifact{
		SchemaVersion: state.PromptPreparationSchemaVersion, Status: state.PromptPreparationFailed,
		ReportID: w.req.Resolved.Definition.ID, RunID: w.metadata.RunID,
		PromptID: w.req.Inspection.PromptID, PromptVersion: w.req.Inspection.PromptVersion,
		DataPackagePath: w.result.DataPackagePath, StartedAt: startedAt, EndedAt: endedAt,
		Error: state.NewPromptArtifactError(executeErr),
	}
	path, err := w.store.SavePromptPreparation(w.ctx, w.req.Resolved, artifact)
	if err != nil {
		return err
	}
	w.result.PreparationPath = path
	w.metadata.PreparationPath = path
	w.result.Metadata = w.metadata
	return w.saveMetadata()
}

func (w *promptReportWorkflow) persistOperationalExecutionFailure(executeErr error) error {
	artifact := failedPromptExecutionArtifact(w.req.Resolved, w.metadata, w.req.Inspection, executeErr)
	path, err := w.store.SavePromptExecution(w.ctx, w.req.Resolved, artifact)
	if err != nil {
		return err
	}
	w.result.ExecutionPath = path
	w.metadata.ExecutionPath = path
	w.result.Metadata = w.metadata
	return w.saveMetadata()
}

func (w *promptReportWorkflow) persistExecutionDebug(execution promptexec.Execution) error {
	debugPath, err := w.req.DebugWriter.WriteExecution(w.debugRef, execution)
	if err != nil {
		return w.reportError("write prompt debug", promptDebugWriteError(err))
	}
	if debugPath != "" {
		w.result.LLMDebugPath = debugPath
	}
	return nil
}

func (w *promptReportWorkflow) persistCompletedExecution(execution promptexec.Execution) error {
	rawPath, err := w.store.SaveGeneratedTextRaw(w.ctx, w.req.Resolved, execution.RawOutput)
	if err != nil {
		return err
	}
	w.result.GeneratedTextRawPath = rawPath
	w.metadata.GeneratedTextRawPath = rawPath
	w.result.Metadata = w.metadata
	w.executionArtifact = state.PromptExecutionArtifact{
		SchemaVersion: state.PromptExecutionSchemaVersion,
		ReportID:      w.req.Resolved.Definition.ID, RunID: w.metadata.RunID,
		PromptID: w.req.Inspection.PromptID, PromptVersion: w.req.Inspection.PromptVersion,
		Provenance: ptr(state.PromptExecutionProvenanceFrom(execution)), Validation: &execution.Validation,
		Paths:     state.PromptExecutionPaths{RawOutputPath: rawPath},
		StartedAt: execution.StartedAt, EndedAt: execution.EndedAt, Duration: execution.Duration,
	}
	if execution.Validation.Status == promptexec.ValidationPassed {
		w.executionArtifact.Status = state.PromptExecutionSucceeded
	} else {
		w.executionArtifact.Status = state.PromptExecutionValidationRejected
	}
	executionPath, err := w.store.SavePromptExecution(w.ctx, w.req.Resolved, w.executionArtifact)
	if err != nil {
		return err
	}
	w.result.ExecutionPath = executionPath
	w.metadata.ExecutionPath = executionPath
	w.result.Metadata = w.metadata
	return w.saveMetadata()
}

func (w *promptReportWorkflow) persistGeneratedContent(raw []byte) ([]byte, error) {
	generatedText, normalized, err := w.handler.Validate(raw)
	if err != nil {
		return nil, w.reportError("validate generated text", err)
	}
	generatedTextPath, err := w.store.SaveGeneratedText(w.ctx, w.req.Resolved, normalized)
	if err != nil {
		return nil, err
	}
	w.result.GeneratedTextPath = generatedTextPath
	w.metadata.GeneratedTextPath = generatedTextPath
	w.result.Metadata = w.metadata
	if err := w.persistReachedPathAndMetadata(func(paths *state.PromptExecutionPaths) { paths.GeneratedTextPath = generatedTextPath }); err != nil {
		return nil, err
	}

	renderContext, err := w.handler.BuildRenderContext(w.briefingMetadata, w.moduleSnapshot, w.reportFacts.Collected, w.reportFacts.Derived, generatedText)
	if err != nil {
		return nil, w.reportError("build render context", err)
	}
	renderContextPath, err := w.store.SaveRenderContext(w.ctx, w.req.Resolved, renderContext)
	if err != nil {
		return nil, err
	}
	w.result.RenderContextPath = renderContextPath
	w.metadata.RenderContextPath = renderContextPath
	w.result.Metadata = w.metadata
	if err := w.persistReachedPathAndMetadata(func(paths *state.PromptExecutionPaths) { paths.RenderContextPath = renderContextPath }); err != nil {
		return nil, err
	}

	rendered, err := w.handler.Render(renderContext)
	if err != nil {
		return nil, w.reportError("render template", err)
	}
	return rendered, nil
}

func (w *promptReportWorkflow) finalizeReport(rendered []byte) (*ReportResult, error) {
	reportPath, err := w.store.PrepareRenderedReport(w.ctx, w.req.Resolved)
	if err != nil {
		return w.result, err
	}
	if err := fileutil.WriteFileAtomic(reportPath, rendered); err != nil {
		return w.result, err
	}
	w.result.ReportPath = reportPath
	w.metadata.RenderedReportPath = reportPath
	w.result.Metadata = w.metadata
	if err := w.persistReachedPath(func(paths *state.PromptExecutionPaths) { paths.RenderedReportPath = reportPath }); err != nil {
		return w.result, err
	}
	finalized, err := finalizeRenderedReport(w.ctx, finalizeRenderedReportRequest{
		Config: w.req.Config, Store: w.store, Resolved: w.req.Resolved, Metadata: w.metadata, MetadataPath: w.result.MetadataPath,
		ExecutionArtifact: &w.executionArtifact, RenderedReportPath: reportPath, OutputPath: w.req.OutputPath,
		Notifier: w.req.Notifier, noNotify: w.req.noNotify,
	})
	w.result.OutputPath = finalized.OutputPath
	w.result.Metadata, w.result.MetadataPath, w.result.Notification = finalized.Metadata, finalized.MetadataPath, finalized.Notification
	return w.result, err
}

func (w *promptReportWorkflow) persistReachedPath(update func(*state.PromptExecutionPaths)) error {
	return persistReachedPromptPath(w.ctx, w.store, w.req.Resolved, &w.executionArtifact, update)
}

func (w *promptReportWorkflow) persistReachedPathAndMetadata(update func(*state.PromptExecutionPaths)) error {
	if err := w.persistReachedPath(update); err != nil {
		return err
	}
	return w.saveMetadata()
}

func (w *promptReportWorkflow) saveMetadata() error {
	path, err := w.store.SaveMetadata(w.ctx, w.metadata)
	if err != nil {
		return err
	}
	w.result.Metadata = w.metadata
	w.result.MetadataPath = path
	return nil
}

func (w *promptReportWorkflow) reportError(operation string, err error) error {
	return generatedReportError(w.req.Resolved, w.metadata.RunID, operation, err)
}

func persistReachedPromptPath(
	ctx context.Context,
	store state.Store,
	resolved report.Resolved,
	artifact *state.PromptExecutionArtifact,
	update func(*state.PromptExecutionPaths),
) error {
	update(&artifact.Paths)
	_, err := store.SavePromptExecution(ctx, resolved, *artifact)
	return err
}

func failedPromptExecutionArtifact(resolved report.Resolved, metadata state.Metadata, inspection PromptInspectionResult, err error) state.PromptExecutionArtifact {
	now := time.Now()
	return state.PromptExecutionArtifact{
		SchemaVersion: state.PromptExecutionSchemaVersion, Status: state.PromptExecutionFailed,
		ReportID: resolved.Definition.ID, RunID: metadata.RunID, PromptID: inspection.PromptID,
		PromptVersion: inspection.PromptVersion, StartedAt: now, EndedAt: now,
		Error: state.NewPromptArtifactError(err),
	}
}

func classifiedPromptError(operation string, err error) error {
	if promptexec.CategoryOf(err) != "" {
		return err
	}
	return promptexec.NewError(promptexec.Generation, operation, err)
}

func promptDebugWriteError(err error) error {
	return promptexec.NewError(promptexec.InvalidConfiguration, "write requested prompt debug artifact", err)
}

func ptr[T any](value T) *T { return &value }