package proposal_generation

import (
	"context"
	"fmt"
	"strings"

	"gitea.maximumdirect.net/eric/audita/internal/core/schema"
	"gitea.maximumdirect.net/eric/audita/internal/framework/contracts"
	"gitea.maximumdirect.net/eric/audita/internal/framework/stagename"
	"gitea.maximumdirect.net/eric/audita/internal/prompts"
)

type ProposalMessageBuilder func(transcript *schema.Transcript, glossary *schema.Glossary, sectionIndex int, transcriptDescription string) ([]contracts.LLMMessage, error)

type ModuleProposalRequest struct {
	ProposalRequest contracts.ProposalRequest
	PromptID        string
	BuildMessages   ProposalMessageBuilder
}

// ExecuteModuleProposal runs shared proposal generation plumbing for one
// module, leaving only module-specific prompt message building at call sites.
func ExecuteModuleProposal(ctx context.Context, req ModuleProposalRequest) (contracts.ProposalResult, error) {
	if req.BuildMessages == nil {
		return contracts.ProposalResult{}, fmt.Errorf("proposal message builder is required")
	}
	if strings.TrimSpace(req.PromptID) == "" {
		return contracts.ProposalResult{}, fmt.Errorf("prompt ID must not be empty")
	}

	sectionIndex := 0
	if req.ProposalRequest.Section != nil {
		sectionIndex = req.ProposalRequest.Section.Index
	}

	transcriptDescription := ""
	if req.ProposalRequest.Config != nil {
		transcriptDescription = req.ProposalRequest.Config.TranscriptDescription
	}

	messages, err := req.BuildMessages(
		req.ProposalRequest.WorkingTranscript,
		req.ProposalRequest.Glossary,
		sectionIndex,
		transcriptDescription,
	)
	if err != nil {
		return contracts.ProposalResult{}, err
	}

	promptMetadata, ok := prompts.LookupMetadata(req.PromptID)
	if !ok {
		return contracts.ProposalResult{}, fmt.Errorf("unknown prompt ID %q", req.PromptID)
	}

	generated, err := GenerateCandidates(ctx, Request{
		ModuleKey:         req.ProposalRequest.RunSpec.ModuleKey,
		ModuleInstance:    req.ProposalRequest.RunSpec.InstanceName,
		ReplacementPolicy: req.ProposalRequest.RunSpec.ReplacementPolicy,
		WorkingTranscript: req.ProposalRequest.WorkingTranscript,
		Section:           req.ProposalRequest.Section,
		Glossary:          req.ProposalRequest.Glossary,
		Config:            req.ProposalRequest.Config,
		Messages:          messages,
		PromptMetadata:    promptMetadata.DiagnosticsMap(),
		StageName:         stagename.ModuleProposal(req.ProposalRequest.RunSpec.InstanceName, sectionIndexPtr(req.ProposalRequest.Section)),
		StartIndex:        0,
		LLMClient:         req.ProposalRequest.LLMClient,
		Scheduler:         req.ProposalRequest.LLMScheduler,
		DiagnosticsDir:    req.ProposalRequest.DiagnosticsDir,
	})
	if err != nil {
		return contracts.ProposalResult{}, err
	}

	return contracts.ProposalResult{
		Proposals: generated.Corrections,
		Warnings:  generated.Warnings,
	}, nil
}