// Package preflight checks resolved processing inputs and prepares output resources.
package preflight

import (
	"context"
	"fmt"

	"gitea.maximumdirect.net/eric/audita/v3/internal/core/config"
	"gitea.maximumdirect.net/eric/audita/v3/internal/core/diagnostics"
	"gitea.maximumdirect.net/eric/audita/v3/internal/core/glossary"
	"gitea.maximumdirect.net/eric/audita/v3/internal/core/modulecatalog"
	"gitea.maximumdirect.net/eric/audita/v3/internal/core/schema"
)

// Input contains already acquired application and transcript inputs.
type Input struct {
	InspectProfile func(context.Context, string) error
	Config         *config.Config
	Transcript     *schema.SourceTranscript
	Output         diagnostics.OutputSelection
	InitialReports diagnostics.ReportBundle
	FailedReports  func(error, []diagnostics.FileFailure) diagnostics.ReportBundle
	Debug          *DebugInput
}

type DebugInput struct {
	WorkDir         string
	RunID           string
	Metadata        diagnostics.InvocationMetadata
	EffectiveConfig []byte
	Secrets         []string
}

type Prepared struct {
	Output   *diagnostics.OutputSession
	Debug    *diagnostics.RunDirectory
	Warnings []error
}

// Prepare validates invocation inputs and collisions before acquiring outputs.
func Prepare(ctx context.Context, input Input) (*Prepared, error) {
	if err := ctx.Err(); err != nil {
		return nil, err
	}
	if input.Config == nil {
		return nil, fmt.Errorf("application configuration is required")
	}
	if input.Transcript == nil {
		return nil, fmt.Errorf("transcript is required")
	}
	if err := CheckReadiness(ctx, input.Config, input.InspectProfile); err != nil {
		return nil, err
	}
	session, err := diagnostics.SelectOutput(input.Output)
	if err != nil {
		return nil, err
	}
	if err := ctx.Err(); err != nil {
		return nil, err
	}
	if err := session.Prepare(); err != nil {
		return nil, err
	}
	if err := ctx.Err(); err != nil {
		_ = session.Close()
		return nil, err
	}
	failedReports := func(primary error) func([]diagnostics.FileFailure) diagnostics.ReportBundle {
		return func(failures []diagnostics.FileFailure) diagnostics.ReportBundle {
			if input.FailedReports == nil {
				return diagnostics.ReportBundle{}
			}
			return input.FailedReports(primary, failures)
		}
	}
	if err := session.Initialize(input.InitialReports, failedReports(nil)); err != nil {
		return nil, err
	}
	cancelOutput := func(err error) error {
		failed := failedReports(err)
		return session.Finish(err, nil, failed(nil), failed)
	}
	if err := ctx.Err(); err != nil {
		return nil, cancelOutput(err)
	}
	result := &Prepared{Output: session}
	if input.Debug != nil {
		result.Debug, result.Warnings = session.PrepareDebug(input.Debug.WorkDir, input.Debug.RunID, input.Debug.Metadata, input.Debug.EffectiveConfig, input.Debug.Secrets...)
	}
	if err := ctx.Err(); err != nil {
		return nil, cancelOutput(err)
	}
	return result, nil
}

// CheckReadiness checks all resolved processing selections before output preparation.
func CheckReadiness(ctx context.Context, cfg *config.Config, inspectProfile func(context.Context, string) error) error {
	if cfg == nil {
		return fmt.Errorf("application configuration is required")
	}
	label := func(index int, item config.Stage) string {
		if item.ID != nil {
			return fmt.Sprintf("stage %d (%s, id %q)", index+1, item.Module, *item.ID)
		}
		return fmt.Sprintf("stage %d (%s)", index+1, item.Module)
	}
	for index, item := range cfg.Pipeline.Stages {
		if item.Module == modulecatalog.KeyGlossary && len(glossary.Select(cfg.GlossaryCollections, item.Glossaries)) == 0 {
			return fmt.Errorf("%s has no glossary entries in selected collections %q", label(index, item), item.Glossaries)
		}
	}
	for index, item := range cfg.Pipeline.Stages {
		for _, selection := range []struct {
			role    string
			profile *string
		}{{"proposal", item.LLM.ProposalProfile}, {"validation", item.LLM.ValidationProfile}} {
			if selection.profile == nil || *selection.profile == "" {
				return fmt.Errorf("%s requires a %s profile", label(index, item), selection.role)
			}
			if inspectProfile == nil {
				return fmt.Errorf("profile inspection is required")
			}
			if err := inspectProfile(ctx, *selection.profile); err != nil {
				return fmt.Errorf("%s %s profile %q: %w", label(index, item), selection.role, *selection.profile, err)
			}
		}
	}
	return ctx.Err()
}