package ckconfig

import (
	"errors"
	"fmt"
	"slices"
	"text/template"

	commandkit "go.maximumdirect.net/commandkit"
	configkit "go.maximumdirect.net/configkit"
)

type validationReport struct {
	Scopes []validationScope `json:"scopes"`
}

type validationScope struct {
	Scope   string             `json:"scope"`
	Outcome string             `json:"outcome"`
	Details *validationDetails `json:"details,omitempty"`
}

type validationDetails struct {
	State    string              `json:"state"`
	Findings []validationFinding `json:"findings"`
	Sources  []validationSource  `json:"sources"`
}

type validationFinding struct {
	Code     string        `json:"code"`
	Severity string        `json:"severity"`
	Path     string        `json:"path"`
	Message  string        `json:"message"`
	Primary  *locationDTO  `json:"primary"`
	Related  []locationDTO `json:"related"`
}

type validationSource struct {
	ID    string `json:"id"`
	Label string `json:"label"`
	Path  string `json:"path"`
}

var validationTextTemplate = template.Must(commandkit.ParseTextTemplate("validation", "{{range .Scopes}}{{.Scope}}: {{.Outcome}}\n{{end}}", nil))
var validationDetailsTemplate = template.Must(commandkit.ParseTextTemplate("validation-details", `{{range .Scopes}}{{.Scope}}: {{.Outcome}} ({{.Details.State}})
{{range .Details.Findings}}  {{.Severity}} {{.Code}} {{printf "%q" .Path}}: {{.Message}}
{{if .Primary}}    {{.Primary.SourceID}}:{{.Primary.Line}}:{{.Primary.Column}}
{{end}}{{range .Related}}    {{.SourceID}}:{{.Line}}:{{.Column}}
{{end}}{{end}}{{range .Details.Sources}}  source {{printf "%q" .ID}}: {{.Label}} {{.Path}}
{{end}}{{end}}`, nil))

func parseValidationSeverity(raw string) (configkit.Severity, error) {
	switch configkit.Severity(raw) {
	case configkit.SeverityError, configkit.SeverityWarning:
		return configkit.Severity(raw), nil
	default:
		return "", fmt.Errorf("unknown validation severity %q", raw)
	}
}

func runConfigValidation[I, S any](invocation commandkit.Invocation, plan *configOperationPlan[I, S], state S) commandkit.Outcome {
	reporter := invocation.Reporter()
	report := validationReport{Scopes: make([]validationScope, 0, len(plan.scopes))}
	outcome := commandkit.Success()
	for _, selected := range plan.scopes {
		if err := invocation.Context.Err(); err != nil {
			outcome = configFailure("Configuration validation was canceled.", commandkit.Explanation{}, err)
			break
		}
		name := selected.scope.scope.Name
		if selected.scope.scope.Acquire == nil {
			entry := validationScope{Scope: name, Outcome: "failed"}
			if plan.details {
				entry.Details = projectValidationDetails(View{}, plan.severities, plan.codes)
			}
			report.Scopes = append(report.Scopes, entry)
			outcome = commandkit.Failure(fmt.Sprintf("Configuration scope %q has no acquisition callback.", name))
			break
		}
		acquired, err := selected.scope.scope.Acquire(invocation.Context, Request{Operation: Validate, Selection: selected.selection}, selected.input, state)
		queueConfigDiagnostics(reporter, acquired.Diagnostics)
		if !plan.details && acquired.Value.Findings != nil {
			queueConfigDiagnostics(reporter, acquired.Value.Findings.Messages)
		}
		entry := validationScope{Scope: name, Outcome: "valid"}
		if plan.details {
			entry.Details = projectValidationDetails(acquired.Value, plan.severities, plan.codes)
		}
		if canceled := invocation.Context.Err(); canceled != nil {
			entry.Outcome = "canceled"
			if err != nil && !errors.Is(err, canceled) {
				err = errors.Join(err, canceled)
			} else if err == nil {
				err = canceled
			}
		} else if err != nil {
			entry.Outcome = "failed"
		}
		report.Scopes = append(report.Scopes, entry)
		if err != nil {
			message := fmt.Sprintf("Unable to validate configuration scope %q.", name)
			if entry.Outcome == "canceled" {
				message = "Configuration validation was canceled."
			}
			outcome = configFailure(message, acquired.Explanation, err)
			break
		}
	}
	text := validationTextTemplate
	if plan.details {
		text = validationDetailsTemplate
	}
	_ = reporter.Report(commandkit.Report{Value: report, TextTemplate: text})
	return outcome
}

func projectValidationDetails(view View, severities []configkit.Severity, codes []string) *validationDetails {
	details := &validationDetails{State: "unavailable", Findings: []validationFinding{}, Sources: []validationSource{}}
	if view.Findings == nil {
		return details
	}
	if len(view.Findings.Records) == 0 {
		details.State = "empty"
		return details
	}
	details.State = "filtered"
	references := make(map[string]bool)
	for _, record := range view.Findings.Records {
		if len(severities) > 0 && !slices.Contains(severities, record.Severity) {
			continue
		}
		if len(codes) > 0 && !slices.Contains(codes, string(record.Code)) {
			continue
		}
		finding := validationFinding{Code: string(record.Code), Severity: string(record.Severity), Path: record.Path.String(), Message: record.Message, Related: locationReports(record.Related)}
		if record.Primary != nil {
			finding.Primary = &locationDTO{SourceID: record.Primary.SourceID, Line: record.Primary.Line, Column: record.Primary.Column}
			references[record.Primary.SourceID] = true
		}
		for _, location := range record.Related {
			references[location.SourceID] = true
		}
		details.Findings = append(details.Findings, finding)
	}
	if len(details.Findings) > 0 {
		details.State = "present"
	}
	if view.Sources != nil {
		for _, source := range view.Sources.Sources() {
			if references[source.ID] {
				details.Sources = append(details.Sources, validationSource{ID: source.ID, Label: source.Label, Path: source.Path})
			}
		}
	}
	return details
}