package ckconfig

import (
	"bytes"
	"fmt"
	"io"
	"strconv"

	commandkit "gitea.maximumdirect.net/eric/CommandKit"
	configkit "gitea.maximumdirect.net/eric/ConfigKit"
	"go.yaml.in/yaml/v4"
)

type sourceReport struct {
	Scope   string      `yaml:"scope"`
	Sources []sourceDTO `yaml:"sources"`
}

type sourceDTO struct {
	ID                    string                 `yaml:"id"`
	Label                 string                 `yaml:"label"`
	Path                  string                 `yaml:"path"`
	Destination           string                 `yaml:"destination"`
	Placement             string                 `yaml:"placement"`
	DestinationUnresolved bool                   `yaml:"destination_unresolved"`
	Layer                 string                 `yaml:"layer"`
	Kind                  string                 `yaml:"kind"`
	UnderlayIndex         int                    `yaml:"underlay_index"`
	ImportedFrom          *locationDTO           `yaml:"imported_from"`
	VersionCheck          *sourceVersionCheckDTO `yaml:"version_check"`
}

type locationDTO struct {
	SourceID string `yaml:"source_id"`
	Line     int    `yaml:"line"`
	Column   int    `yaml:"column"`
}

type sourceVersionCheckDTO struct {
	Path     string       `yaml:"path"`
	Version  versionDTO   `yaml:"version"`
	Location *locationDTO `yaml:"location"`
	Redacted bool         `yaml:"redacted"`
}

type versionDTO struct {
	Present bool   `yaml:"present"`
	Null    bool   `yaml:"null"`
	Text    string `yaml:"text"`
}

func runConfigSources[I, S any](invocation commandkit.Invocation, plan *configOperationPlan[I, S], state S) commandkit.Outcome {
	selected := plan.scopes[0]
	name := selected.scope.scope.Name
	reporter := invocation.Reporter()
	if err := invocation.Context.Err(); err != nil {
		return configFailure("Configuration source listing was canceled.", commandkit.Explanation{}, err)
	}
	if selected.scope.scope.Acquire == nil {
		cause := fmt.Errorf("configuration scope %q has no acquisition callback", name)
		return configFailure(fmt.Sprintf("Unable to list sources for configuration scope %q.", name), commandkit.Explanation{}, cause)
	}
	acquired, acquireErr := selected.scope.scope.Acquire(invocation.Context, Request{
		Operation: Sources,
		Selection: plan.selection,
	}, selected.input, state)
	queueConfigDiagnostics(reporter, acquired.Diagnostics)
	if acquireErr != nil {
		return configFailure(fmt.Sprintf("Unable to list sources for configuration scope %q.", name), acquired.Explanation, acquireErr)
	}
	if err := invocation.Context.Err(); err != nil {
		return configFailure("Configuration source listing was canceled.", acquired.Explanation, err)
	}
	if acquired.Value.Sources == nil {
		cause := fmt.Errorf("configuration scope %q did not provide a source reader", name)
		return configFailure("Configuration scope did not provide source information.", acquired.Explanation, cause)
	}

	sources := acquired.Value.Sources.Sources()
	document := sourceReport{Scope: name, Sources: make([]sourceDTO, 0, len(sources))}
	for _, source := range sources {
		placement := "mapping"
		if source.PlacementMode == configkit.PlacementModeSequenceItem {
			placement = "sequence_item"
		}
		item := sourceDTO{
			ID:                    source.ID,
			Label:                 source.Label,
			Path:                  source.Path,
			Destination:           source.Destination.String(),
			Placement:             placement,
			DestinationUnresolved: source.DestinationUnresolved,
			Layer:                 string(source.Layer),
			Kind:                  string(source.Kind),
			UnderlayIndex:         source.UnderlayIndex,
		}
		if source.ImportedFrom != nil {
			item.ImportedFrom = &locationDTO{SourceID: source.ImportedFrom.SourceID, Line: source.ImportedFrom.Line, Column: source.ImportedFrom.Column}
		}
		if source.VersionCheck != nil {
			check := source.VersionCheck
			item.VersionCheck = &sourceVersionCheckDTO{
				Path: check.Path.String(),
				Version: versionDTO{
					Present: check.Version.Present,
					Null:    check.Version.Null,
					Text:    check.Version.Text,
				},
				Redacted: check.Redacted,
			}
			if check.Location != nil {
				item.VersionCheck.Location = &locationDTO{SourceID: check.Location.SourceID, Line: check.Location.Line, Column: check.Location.Column}
			}
		}
		document.Sources = append(document.Sources, item)
	}
	if err := invocation.Context.Err(); err != nil {
		return configFailure("Configuration source listing was canceled.", acquired.Explanation, err)
	}
	err := reporter.RenderOutput(func(writer io.Writer) error {
		var report bytes.Buffer
		if plan.format == "yaml" {
			if err := encodeYAML(&report, document); err != nil {
				return err
			}
		} else {
			writeSourceReportText(&report, document)
		}
		_, err := writer.Write(report.Bytes())
		return err
	})
	if err != nil && invocation.Context.Err() != nil {
		return configFailure("Configuration source listing was canceled.", acquired.Explanation, invocation.Context.Err())
	}
	return commandkit.Success()
}

func writeSourceReportText(writer *bytes.Buffer, document sourceReport) {
	_, _ = fmt.Fprintf(writer, "Scope: %s\n", strconv.Quote(document.Scope))
	if len(document.Sources) == 0 {
		_, _ = writer.WriteString("Sources: []\n")
		return
	}
	_, _ = writer.WriteString("Sources:\n")
	for _, source := range document.Sources {
		_, _ = fmt.Fprintf(writer, "  - id: %s\n", strconv.Quote(source.ID))
		_, _ = fmt.Fprintf(writer, "    label: %s\n", strconv.Quote(source.Label))
		_, _ = fmt.Fprintf(writer, "    path: %s\n", strconv.Quote(source.Path))
		_, _ = fmt.Fprintf(writer, "    destination: %s\n", strconv.Quote(source.Destination))
		_, _ = fmt.Fprintf(writer, "    placement: %s\n", strconv.Quote(source.Placement))
		_, _ = fmt.Fprintf(writer, "    destination_unresolved: %t\n", source.DestinationUnresolved)
		_, _ = fmt.Fprintf(writer, "    layer: %s\n", strconv.Quote(source.Layer))
		_, _ = fmt.Fprintf(writer, "    kind: %s\n", strconv.Quote(source.Kind))
		_, _ = fmt.Fprintf(writer, "    underlay_index: %d\n", source.UnderlayIndex)
		if source.ImportedFrom == nil {
			_, _ = writer.WriteString("    imported_from: null\n")
		} else {
			_, _ = fmt.Fprintf(writer, "    imported_from: {source_id: %s, line: %d, column: %d}\n",
				strconv.Quote(source.ImportedFrom.SourceID), source.ImportedFrom.Line, source.ImportedFrom.Column)
		}
		if source.VersionCheck == nil {
			_, _ = writer.WriteString("    version_check: null\n")
			continue
		}
		check := source.VersionCheck
		_, _ = fmt.Fprintf(writer, "    version_check:\n      path: %s\n", strconv.Quote(check.Path))
		_, _ = fmt.Fprintf(writer, "      version:\n        present: %t\n        null: %t\n        text: %s\n",
			check.Version.Present, check.Version.Null, strconv.Quote(check.Version.Text))
		if check.Location == nil {
			_, _ = writer.WriteString("      location: null\n")
		} else {
			_, _ = fmt.Fprintf(writer, "      location: {source_id: %s, line: %d, column: %d}\n",
				strconv.Quote(check.Location.SourceID), check.Location.Line, check.Location.Column)
		}
		_, _ = fmt.Fprintf(writer, "      redacted: %t\n", check.Redacted)
	}
}

func encodeYAML(writer io.Writer, document any) error {
	encoder := yaml.NewEncoder(writer)
	encoder.SetIndent(2)
	return encoder.Encode(document)
}

func locationReports(locations []configkit.Location) []locationDTO {
	report := make([]locationDTO, 0, len(locations))
	for _, location := range locations {
		report = append(report, locationDTO{SourceID: location.SourceID, Line: location.Line, Column: location.Column})
	}
	return report
}