package commandkit

import (
	"bytes"
	"fmt"
	"strings"

	"go.yaml.in/yaml/v4"
)

func configOperationDeclared[C any](scopes []ConfigScope[C], operation ConfigOperation) bool {
	for _, scope := range scopes {
		if containsOperation(scope.Operations, operation) {
			return true
		}
	}
	return false
}

func newConfigValidateCommand[C any](suite ConfigSuite[C]) (Command, error) {
	spec := CommandSpec[configInput[C]]{
		Name:    string(ConfigValidate),
		Summary: "Validate selected configuration scopes.",
		Flags:   configInputFlags(suite, "text"),
		CheckInput: func(input configInput[C]) error {
			_, err := preflightConfig(suite, input, ConfigValidate)
			return err
		},
		Run: func(invocation Invocation, input configInput[C]) Outcome {
			return runConfigValidation(invocation, suite, input)
		},
	}
	return NewCommand(spec)
}

func runConfigValidation[C any](invocation Invocation, suite ConfigSuite[C], input configInput[C]) Outcome {
	if err := invocation.Context.Err(); err != nil {
		return Failure(err)
	}
	scopeNames, err := selectConfigScopes(suite, input, ConfigValidate)
	if err != nil {
		return Failure(err)
	}
	contexts := contextsForScopes(suite, input, scopeNames)
	diagnostics := make([]Diagnostic, 0)
	writtenRecord := false
	for _, name := range scopeNames {
		scope, ok := findConfigScope(suite.Scopes, name)
		if !ok || scope.Acquire == nil {
			return validationFailure(fmt.Errorf("configuration scope %q has no acquisition callback", name), diagnostics, writtenRecord)
		}
		if err := invocation.Context.Err(); err != nil {
			return validationFailure(err, diagnostics, writtenRecord)
		}
		acquired, acquireErr := scope.Acquire(invocation.Context, ConfigRequest{Operation: ConfigValidate, Selection: input.Selection}, contexts[name])
		diagnostics = append(diagnostics, acquired.Diagnostics...)
		if acquireErr != nil {
			return validationFailure(acquireErr, diagnostics, writtenRecord)
		}

		if err := invocation.Context.Err(); err != nil {
			return validationFailure(err, diagnostics, writtenRecord)
		}

		record, err := validationSuccessRecord(name, input.Format)
		if err != nil {
			return validationFailure(err, diagnostics, writtenRecord)
		}
		if input.Format == "yaml" && !writtenRecord {
			if err := writeReport(invocation.Streams.Out, []byte("scopes:\n")); err != nil {
				outcome := validationFailure(err, diagnostics, true)
				outcome.DeliveryError = err
				return outcome
			}
		}
		if err := writeReport(invocation.Streams.Out, record); err != nil {
			outcome := validationFailure(err, diagnostics, true)
			outcome.DeliveryError = err
			return outcome
		}
		writtenRecord = true
	}
	outcome := Success()
	outcome.Diagnostics = diagnostics
	return outcome
}

func validationFailure(cause error, diagnostics []Diagnostic, reportStarted bool) Outcome {
	outcome := Failure(cause)
	outcome.Diagnostics = diagnostics
	outcome.ReportIncomplete = reportStarted
	return outcome
}

func validationSuccessRecord(scope, format string) ([]byte, error) {
	if format == "text" {
		return []byte(scope + ": valid\n"), nil
	}
	encoded, err := yaml.Marshal(struct {
		Name  string `yaml:"name"`
		Valid bool   `yaml:"valid"`
	}{Name: scope, Valid: true})
	if err != nil {
		return nil, err
	}
	lines := strings.Split(strings.TrimSuffix(string(encoded), "\n"), "\n")
	var record bytes.Buffer
	for index, line := range lines {
		if index == 0 {
			record.WriteString("  - ")
		} else {
			record.WriteString("    ")
		}
		record.WriteString(line)
		record.WriteByte('\n')
	}
	return record.Bytes(), nil
}