package Torello.Java;

import static Torello.Java.C.*;

import java.util.Arrays;

/**
 * <B><CODE>'Exception Cause Chain'</CODE></B> helps convert exception messages whose
 * <CODE><B>Throwable.cause()</B></CODE> method returns a non-null <CODE>cause</CODE>, thereby
 * unrolling <I>(and printing)</I> this chain of exceptions into a readable <CODE>String</CODE>.
 * 
 * <EMBED CLASS=external-html DATA-FILE-ID=EXCC>
 */
@Torello.JavaDoc.StaticFunctional
public class EXCC
{
    private EXCC() { }

    /**
     * Convenience Method.
     * <BR />Invokes: {@link #toString(Throwable)}
     * <BR />And-Then: {@link StrIndent#indentTabs(String, int)}
     */
    public static String toString(Throwable t, int indentation)
    { return StrIndent.indentTabs(toString(t), indentation); }

    /**
     * Prints the {@code Exception}-message and {@code Exception}-stack trace to an output
     * {@code String}, and invokes, recursively, this method with any cause-{@code Throwable's}
     * that are present in this {@code Throwable}.
     *
     * @param t Any Java {@code Throwable}.  Java {@code Throwable's} with one or {@code 'cause'}
     * {@code Throwable's} will utilize more fully the printing-features of this class,
     * {@code 'EXCC'} - <I>though any {@code Throwable} will be properly printed</I>.
     * 
     * @return This method doesn't actually print anything to the screen or terminal, it just
     * returns a {@code String} that you may print yourself - <I>or write to a
     * {@code class StringBuilder}, or any variation of text-output you wish.</I>
     */
    public static String toString(Throwable t)
    {
        StackTraceElement[] steArr      = t.getStackTrace();
        StringBuilder       sb          = new StringBuilder();
        Throwable           cause       = t.getCause();
        String              m           = t.getMessage();
        String              lm          = t.getLocalizedMessage();
        boolean             hasMessage  = (m != null) && (m.length() > 0);
        boolean             hasLMess    = (lm != null) && (lm.length() > 0);

        if (hasMessage) m   = StrIndent.indent(m, 1, false, true);
        if (hasLMess)   lm  = StrIndent.indent(lm, 1, false, true);

        sb.append(BRED + "THROWN: " + t.getClass().getCanonicalName() + RESET + "\n");

        if (hasMessage)
        {
            sb.append(BCYAN + "Throwable.getMessage():\n" + RESET + m + "\n");

            if (hasLMess && (! m.equals(lm)))
                sb.append(BCYAN + "Throwable.getLocalizedMessage():\n" + RESET + lm + "\n");
        }

        else if (hasLMess)
            sb.append(BCYAN + "Throwable.getLocalizedMessage():\n" + RESET + lm + "\n");

        else
            sb.append(BYELLOW + "No Exception Messages Provided.\n" + RESET);

        sb.append(BCYAN + "StackTrace:\n" + RESET);

        int temp, maxLN = 0;

        for (StackTraceElement ste : steArr)

            if ((temp = ste.getLineNumber()) > maxLN)
                maxLN = temp;

        int base10 = 2 /* 2: colon + space */ + ((int) Math.ceil(Math.log10(maxLN)));

        for (int k=0; k < steArr.length; k++)

            sb.append(
                '\t' + StringParse.rightSpacePad(steArr[k].getLineNumber() + ":", base10) +
                steArr[k].getClassName() + "." +
                steArr[k].getMethodName() + "()\n"
            );

        return (cause == null)
            ? sb.toString()
            : sb.toString() + StrIndent.indentTabs(toString(cause), 1);
    }

    /**
     * Convenience Method.
     * <BR />Invokes: {@link #toStringMaxTraces(Throwable, int)}
     * <BR />And-Then: {@link StrIndent#indentTabs(String, int)}
     */
    public static String toStringMaxTraces(Throwable t, int maxNumInvocations, int indentation)
    { return StrIndent.indent(toStringMaxTraces(t, maxNumInvocations), indentation); }

    /**
     * Prints the {@code Exception}-message and {@code Exception}-stack trace to an output
     * {@code String}, and invokes, recursively, this method with any cause-{@code Throwable's}
     * that are present in this {@code Throwable}.
     *
     * @param t Any Java {@code Throwable}.  Java {@code Throwable's} with one or {@code 'cause'}
     * {@code Throwable's} will utilize more fully the printing-features of this class,
     * {@code 'EXCC'} - <I>though any {@code Throwable} will be properly printed</I>.
     * 
     * @param maxNumInvocations Each of the {@code Throwable's} printed shall have, at most,
     * {@code 'maxNumInvocations'} of their Stack-Traces printed into the output {@code String}.
     * 
     * @return This method doesn't actually print anything to the screen or terminal, it just
     * returns a {@code String} that you may print yourself - <I>or write to a
     * {@code class StringBuilder}, or any variation of text-output you wish.</I>
     */
    public static String toStringMaxTraces(Throwable t, int maxNumInvocations)
    {
        StackTraceElement[] steArr      = t.getStackTrace();
        StringBuilder       sb          = new StringBuilder();
        Throwable           cause       = t.getCause();
        String              m           = t.getMessage();
        String              lm          = t.getLocalizedMessage();
        boolean             hasMessage  = (m != null) && (m.length() > 0);
        boolean             hasLMess    = (lm != null) && (lm.length() > 0);

        if (hasMessage) m   = StrIndent.indent(m, 1, false, true);
        if (hasLMess)   lm  = StrIndent.indent(lm, 1, false, true);

        sb.append(BRED + "THROWN: " + t.getClass().getCanonicalName() + RESET + "\n");

        if (hasMessage)
        {
            sb.append(BCYAN + "Throwable.getMessage():\n" + RESET + m + "\n");

            if (hasLMess && (! m.equals(lm)))
                sb.append(BCYAN + "Throwable.getLocalizedMessage():\n" + RESET + lm + "\n");
        }

        else if (hasLMess)
            sb.append(BCYAN + "Throwable.getLocalizedMessage():\n" + RESET + lm + "\n");

        else
            sb.append(BYELLOW + "No Exception Messages Provided.\n" + RESET);

        sb.append(BCYAN + "StackTrace:\n" + RESET);

        int temp, maxLN = 0;

        int stTruncated = 0;

        if (steArr.length > maxNumInvocations)
        {
            stTruncated = steArr.length - maxNumInvocations;
            steArr = Arrays.copyOf(steArr, maxNumInvocations);
        }

        for (StackTraceElement ste : steArr)

            if ((temp = ste.getLineNumber()) > maxLN)
                maxLN = temp;

        int base10 = 2 /* 2: colon + space */ + ((int) Math.ceil(Math.log10(maxLN)));

        for (int k=0; k < steArr.length; k++)

            sb.append(
                '\t' + StringParse.rightSpacePad(steArr[k].getLineNumber() + ":", base10) +
                steArr[k].getClassName() + "." +
                steArr[k].getMethodName() + "()\n"
            );

        if (stTruncated > 0) sb.append("\t... and " + stTruncated + " more invocations.\n");

        return (cause == null)
            ? sb.toString()
            : sb.toString() + StrIndent.indentTabs(toString(cause), 1);
    }

    /**
     * Convenience Method.
     * <BR />Invokes: {@link #toStringNoST(Throwable)}
     * <BR />And-Then: {@link StrIndent#indentTabs(String, int)}
     */
    public static String toStringNoST(Throwable t, int indentation)
    { return StrIndent.indentTabs(toStringNoST(t), indentation); }

    /**
     * Prints the {@code Exception}-message to an output {@code String}.  Invokes, recursively,
     * this method with any cause-{@code Throwable's} that are present in this {@code Throwable}.
     *
     * <BR /><BR />This method differs from {@link #toString(Throwable)}, in that it <I>does not
     * print the {@code StackTrace's} to the output {@code String}.</I>
     * 
     * @param t Any Java {@code Throwable}.  Java {@code Throwable's} with one or {@code 'cause'}
     * {@code Throwable's} will utilize more fully the printing-features of this class,
     * {@code 'EXCC'} - <I>though any {@code Throwable} will be properly printed</I>.
     * 
     * @return This method doesn't actually print anything to the screen or terminal, it just
     * returns a {@code String} that you may print yourself - <I>or write to a
     * {@code class StorageBuffer,} or any variation of logging you wish.</I>
     */
    public static String toStringNoST(Throwable t)
    {
        StringBuilder       sb          = new StringBuilder();
        Throwable           cause       = t.getCause();
        String              m           = t.getMessage();
        String              lm          = t.getLocalizedMessage();
        boolean             hasMessage  = (m != null) && (m.length() > 0);
        boolean             hasLMess    = (lm != null) && (lm.length() > 0);

        if (hasMessage) m   = StrIndent.indent(m, 1, false, true);
        if (hasLMess)   lm  = StrIndent.indent(lm, 1, false, true);

        sb.append(BRED + "THROWN: " + t.getClass().getCanonicalName() + RESET + "\n");

        if (hasMessage)
        {
            sb.append(BCYAN + "Throwable.getMessage():\n" + RESET + m + "\n");

            if (hasLMess && (! m.equals(lm)))
                sb.append(BCYAN + "Throwable.getLocalizedMessage():\n" + RESET + lm + "\n");
        }

        else if (hasLMess)
            sb.append(BCYAN + "Throwable.getLocalizedMessage():\n" + RESET + lm + "\n");

        else
            sb.append(BYELLOW + "No Exception Messages Provided.\n" + RESET);

        return (cause == null)
            ? sb.toString()
            : sb.toString() + StrIndent.indentTabs(toStringNoST(cause), 1);
    }

}