package normalize

import (
	"fmt"
	"path/filepath"
	"sort"
	"strings"

	"gitea.maximumdirect.net/eric/seriatim/internal/artifact"
	"gitea.maximumdirect.net/eric/seriatim/internal/buildinfo"
	"gitea.maximumdirect.net/eric/seriatim/internal/config"
	"gitea.maximumdirect.net/eric/seriatim/schema"
)

// Build converts parsed normalize input into a selected seriatim output schema.
func Build(parsed ParsedTranscript, cfg config.NormalizeConfig) (any, error) {
	ordered := sortedSegments(parsed.Segments)

	switch cfg.OutputSchema {
	case config.OutputSchemaMinimal:
		output := buildMinimal(ordered)
		if err := schema.ValidateMinimalTranscript(output); err != nil {
			return nil, fmt.Errorf("validate normalize output: %w", err)
		}
		return output, nil
	case config.OutputSchemaIntermediate:
		output := buildIntermediate(ordered)
		if err := schema.ValidateIntermediateTranscript(output); err != nil {
			return nil, fmt.Errorf("validate normalize output: %w", err)
		}
		return output, nil
	case config.OutputSchemaFull:
		output := buildFull(ordered, cfg)
		if err := schema.ValidateTranscript(output); err != nil {
			return nil, fmt.Errorf("validate normalize output: %w", err)
		}
		return output, nil
	default:
		return nil, fmt.Errorf("unsupported output schema %q", cfg.OutputSchema)
	}
}

func sortedSegments(input []InputSegment) []InputSegment {
	ordered := make([]InputSegment, len(input))
	copy(ordered, input)
	sort.SliceStable(ordered, func(i, j int) bool {
		left := ordered[i]
		right := ordered[j]
		if left.Start != right.Start {
			return left.Start < right.Start
		}
		if left.End != right.End {
			return left.End < right.End
		}
		if left.InputIndex != right.InputIndex {
			return left.InputIndex < right.InputIndex
		}
		return left.Speaker < right.Speaker
	})
	return ordered
}

func buildMinimal(segments []InputSegment) schema.MinimalTranscript {
	outputSegments := make([]schema.MinimalSegment, len(segments))
	for index, segment := range segments {
		outputSegments[index] = schema.MinimalSegment{
			ID:      index + 1,
			Start:   segment.Start,
			End:     segment.End,
			Speaker: segment.Speaker,
			Text:    segment.Text,
		}
	}

	return schema.MinimalTranscript{
		Metadata: schema.MinimalMetadata{
			Application:  artifact.ApplicationName,
			Version:      buildinfo.Version,
			OutputSchema: config.OutputSchemaMinimal,
		},
		Segments: outputSegments,
	}
}

func buildIntermediate(segments []InputSegment) schema.IntermediateTranscript {
	outputSegments := make([]schema.IntermediateSegment, len(segments))
	for index, segment := range segments {
		outputSegments[index] = schema.IntermediateSegment{
			ID:         index + 1,
			Start:      segment.Start,
			End:        segment.End,
			Speaker:    segment.Speaker,
			Text:       segment.Text,
			Categories: append([]string(nil), segment.Categories...),
		}
	}

	return schema.IntermediateTranscript{
		Metadata: schema.IntermediateMetadata{
			Application:  artifact.ApplicationName,
			Version:      buildinfo.Version,
			OutputSchema: config.OutputSchemaIntermediate,
		},
		Segments: outputSegments,
	}
}

func buildFull(segments []InputSegment, cfg config.NormalizeConfig) schema.Transcript {
	defaultSource := filepath.Base(cfg.InputFile)
	outputSegments := make([]schema.Segment, len(segments))
	for index, segment := range segments {
		source := strings.TrimSpace(segment.Source)
		if source == "" {
			source = defaultSource
		}

		sourceSegmentIndex := copyIntPtr(segment.SourceSegmentIndex)
		if sourceSegmentIndex == nil {
			fallback := segment.InputIndex
			sourceSegmentIndex = &fallback
		}

		outputSegments[index] = schema.Segment{
			ID:                 index + 1,
			Source:             source,
			SourceSegmentIndex: sourceSegmentIndex,
			SourceRef:          segment.SourceRef,
			DerivedFrom:        append([]string(nil), segment.DerivedFrom...),
			Speaker:            segment.Speaker,
			Start:              segment.Start,
			End:                segment.End,
			Text:               segment.Text,
			Categories:         append([]string(nil), segment.Categories...),
		}
	}

	return schema.Transcript{
		Metadata: schema.Metadata{
			Application:           artifact.ApplicationName,
			Version:               buildinfo.Version,
			InputReader:           "normalize-input",
			InputFiles:            []string{cfg.InputFile},
			PreprocessingModules:  []string{},
			PostprocessingModules: []string{},
			OutputModules:         append([]string(nil), cfg.OutputModules...),
		},
		Segments:      outputSegments,
		OverlapGroups: []schema.OverlapGroup{},
	}
}

func copyIntPtr(value *int) *int {
	if value == nil {
		return nil
	}
	copied := *value
	return &copied
}