package llm

import (
	"context"
	"encoding/json"
	"fmt"
	"strings"
	"time"

	"gitea.maximumdirect.net/eric/audita/internal/framework/responseschema"
	"gitea.maximumdirect.net/eric/audita/internal/framework/structuredoutput"
	"gitea.maximumdirect.net/eric/audita/internal/prompts"
	pk "gitea.maximumdirect.net/eric/promptkit"
)

// CallHooks receive one logical start and finish record and the execution
// events for this call. Call records can contain transcript content.
type CallHooks struct {
	OnCall  func(structuredoutput.CallRecord)
	OnEvent pk.ExecutionObserver
}

type RoleClient struct {
	runtime *Runtime
	role    string
	hooks   CallHooks
}

var _ structuredoutput.Client = (*RoleClient)(nil)

func (r *Runtime) NewRoleClient(role string, hooks CallHooks) (*RoleClient, error) {
	if _, ok := r.Profiles[role]; !ok {
		return nil, fmt.Errorf("unknown LLM role %q", role)
	}
	return &RoleClient{runtime: r, role: role, hooks: hooks}, nil
}

func (c *RoleClient) CompleteStructured(parent context.Context, req structuredoutput.Request, out any) (response structuredoutput.Response, err error) {
	ctx, cancel := context.WithTimeout(parent, c.runtime.Config.LLM.OperationTimeout)
	defer cancel()
	record := structuredoutput.CallRecord{Context: req.Context, Started: time.Now().UTC()}
	record.Context.Role = c.role
	if c.hooks.OnCall != nil {
		c.hooks.OnCall(record)
	}
	defer func() {
		record.Finished = time.Now().UTC()
		if err != nil {
			if structuredoutput.IsMalformedError(err) {
				record.Failure = structuredoutput.FailureMalformedOutput
			} else {
				record.Failure = structuredoutput.FailureRuntime
			}
		}
		if c.hooks.OnCall != nil {
			c.hooks.OnCall(record)
		}
	}()
	if err = validateOutputTarget(out); err != nil {
		return response, &structuredoutput.Failure{Kind: structuredoutput.FailureRuntime, Message: "invalid structured output target", Cause: err}
	}
	schemaPath, ok := responseschema.AssetPath(req.Schema)
	if !ok {
		return response, &structuredoutput.Failure{Kind: structuredoutput.FailureRuntime, Message: "unknown structured response schema", Cause: fmt.Errorf("schema %q", req.Schema)}
	}
	profile := c.runtime.Profiles[c.role]
	backend := c.runtime.Config.Backends[profile.EffectiveModelParams.BackendID]
	vars := make(map[string]string, len(req.Variables)+1)
	for key, value := range req.Variables {
		vars[key] = value
	}
	vars["HardeningPolicy"] = prompts.HardeningText()
	apiKey := ""
	if backend.Credential != nil {
		apiKey = backend.Credential.Value()
	}
	handle, prepErr := c.runtime.Engine.PrepareExecution(ctx, pk.RunRequest{
		PromptID: req.PromptID, PromptVersion: req.PromptVersion,
		ProfileID: profile.ProfileID, APIKey: apiKey, Vars: vars,
		Validation: &pk.OutputContract{Format: pk.FormatJSON, ValidationMode: pk.ValidationJSONSchema, SchemaPath: schemaPath, RepairAttempts: c.runtime.Config.LLM.RepairAttempts},
		Observer:   c.hooks.OnEvent,
	})
	if prepErr != nil {
		return response, &structuredoutput.Failure{Kind: structuredoutput.FailureRuntime, Message: "could not prepare structured model call", Cause: prepErr}
	}
	defer handle.Discard()
	details := handle.Details()
	response.Prompt = promptMetadata(details)
	response.Model = details.EffectiveModelParams.Model
	response.Prepared = preparedSnapshot(details)
	record.Prepared = response.Prepared
	selected, exists := c.runtime.Config.Backends[details.SelectedBackendID]
	endpoint := func(s string) string { return strings.TrimRight(strings.TrimSpace(s), "/") }
	if !exists || details.SelectedProfileID != profile.ProfileID || details.SelectedBackendID != profile.EffectiveModelParams.BackendID || endpoint(details.EffectiveModelParams.Endpoint) != endpoint(selected.Endpoint) || details.EffectiveModelParams.APIKeyEnv != "" {
		return response, &structuredoutput.Failure{Kind: structuredoutput.FailureRuntime, Message: "structured model target changed after configuration inspection", Cause: fmt.Errorf("prepared target does not match registered role backend")}
	}
	result, runErr := c.runtime.Engine.RunPrepared(ctx, handle)
	if result != nil {
		response.FinalContent = result.RawOutput
		record.FinalContent = result.RawOutput
		response.Model = result.ModelName
		response.PromptTokens = result.Usage.PromptTokens
		response.CompletionTokens = result.Usage.CompletionTokens
		response.TotalTokens = result.Usage.TotalTokens
	}
	if runErr != nil {
		return response, &structuredoutput.Failure{Kind: structuredoutput.FailureRuntime, Message: "structured model call failed", Cause: runErr}
	}
	if result == nil {
		return response, &structuredoutput.Failure{Kind: structuredoutput.FailureRuntime, Message: "structured model call returned no result"}
	}
	if !result.Validation.IsValid {
		return response, &structuredoutput.Failure{Kind: structuredoutput.FailureMalformedOutput, Message: "malformed structured output"}
	}
	if decodeErr := json.Unmarshal([]byte(result.RawOutput), out); decodeErr != nil {
		return response, &structuredoutput.Failure{Kind: structuredoutput.FailureRuntime, Message: "validated structured output could not be decoded", Cause: decodeErr}
	}
	response.Content = json.RawMessage(result.RawOutput)
	response.Provider = "openai-compatible"
	return response, nil
}

func promptMetadata(details pk.PreparedRun) structuredoutput.PromptMetadata {
	return structuredoutput.PromptMetadata{
		PromptID: details.PromptID, PromptVersion: details.PromptVersion,
		DefinitionHash: details.PromptHash, RenderedHash: details.RenderedPromptHash,
		ProfileID: details.SelectedProfileID, BackendID: details.SelectedBackendID,
		Model: details.EffectiveModelParams.Model,
	}
}

func preparedSnapshot(details pk.PreparedRun) *structuredoutput.PreparedSnapshot {
	messages := make([]structuredoutput.Message, len(details.Messages))
	for i, message := range details.Messages {
		messages[i] = structuredoutput.Message{Role: string(message.Role), Content: message.Content}
	}
	return &structuredoutput.PreparedSnapshot{Messages: messages, Prompt: promptMetadata(details)}
}